128501009 has 24 divisors (see below), whose sum is σ = 167423040. Its totient is φ = 96303168.

The previous prime is 128500993. The next prime is 128501029. The reversal of 128501009 is 900105821.

It is a happy number.

It is not a de Polignac number, because 128501009 - 2⁴ = 128500993 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (128501029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19619 + ... + 25335.

It is an arithmetic number, because the mean of its divisors is an integer number (6975960).

Almost surely, 2^128501009 is an apocalyptic number.

128501009 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

128501009 is a deficient number, since it is larger than the sum of its proper divisors (38922031).

128501009 is a wasteful number, since it uses less digits than its factorization.

128501009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5769 (or 5756 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 128501009 is about 11335.8285537494. The cubic root of 128501009 is about 504.6250970376.

The spelling of 128501009 in words is "one hundred twenty-eight million, five hundred one thousand, nine".